1. Field of the Invention
This invention concerns improvements in and relating to door openers, that is mechanism which can be used for opening of doors, in particular, doors of the type which are commonly described as "tip-up" doors such, for example, as are commonly used for garages or similar large openings.
The invention is applicable to this kind of door mechanism adapted for tip-up opening of a door by running in vertical channels also with the channels adapted to operation in other orientations in space, for example, horizontally.
2. Description of the Related Art
Tip-up doors typically comprise rollers provided at an intermediate height of the left hand and right hand vertical sides of the door to run in vertical channels in the door frame and link or other type mechanisms to control a "tip-up" action whereby the door rotates from a vertical position to a horizontal position when it is opened by lifting it upwards, generally with means of counterbalancing the weight of the door. Motor driven opening of such doors has been described in arrangements where a motor is mounted on fixed structure and drives levers or cables or screws to actuate the door for opening and closing.